Conventionally, there has been disclosed a power supply circuit technique which performs PWM (Pulse Width Modulation) control when the load is heavy and which, when the load is light, switches to PFM (Pulse Frequency Modulation) control.
However, when the control mode of the power supply circuit is switched between PWM control and PFM control, a ripple may occur in output voltage, causing variation in the output voltage. Accordingly, a technique is desired which lessens a ripple in the output voltage when the control mode is switched between PWM control and PFM control.